Terminal connector



Jan. 11, 1955 L. H. FLORA 2,699,535

TERMINAL CONNECTOR Filed Jan. 5, 1953 INVENTOR 4065 1/66 A! 50/64 ATTORNEY United States Patent TERMINAL CONNECTOR Laurence H. Flora, Cleveland, Ohio, assignor t0 Tinnerman Products, inc, Cleveland, Ohio, a corporation of Uhio Application January 5, 1953, Serial No. 329,514

It Claims. (Cl. 339-263) This invention relates in general to electrical terminal connections and deals, more particularly, with an improved construction of a terminal connector or adapter for spark plugs, and the like, in the form of a sheet metal shell or sleeve that is equally effective in use as the usual solid metal terminal connector, and which is preferable in many instances in that it is considerably cheaper in cost of manufacture and otherwise adapted to be attached to a threaded terminal in a thread locking action to provide a locked terminal connection which is not subject to loosening or removal under the most severe conditions of vibration.

A primary object of the invention is to provide a sheet metal terminal connector or adapter in the form of a generally tubular body similar to a shell or sleeve and having one or more groups of generally horizontal flutes or grooves formed on its inner surface defining thread elements for threadedly engaging the usual threaded electrode or binding post in a spark plug or other electrical device, and preferably in a friction or press fit providing for a thread locking action of the terminal connector or adapter in attached position.

A further object of the invention is to provide a sheet metal terminal connector or adapter of this character in which the thread elements defined by said groups of generally horizontal flutes or grooves on the inner surface of the connector are formed on a helix corresponding substantially to the helix of the thread on the electrode or binding post for uniform threaded engagement therewith in the manner of a threaded nut.

Another object of the invention is to provide a terminal connector or adapter, as described, in a simple onepiece device formed from a blank of sheet metal that is rolled into a split tubular body similar to a shell or sleeve and provided with spaced bosses or protuberances on the inner surface thereof on which there are formed the groups of generally horizontal flutes or grooves defining the thread elements for threadedly engaging a threaded binding post in a spark plug, or the like, in a resilient thread locking action which prevents accidental loosening or removal of the connector from attached position.

A further object of the invention is to provide such a sheet metal terminal connector or adapter in which the split tubular body of the connector is provided with interconnecting or locking means on the portions adjoining the split in said tubular body for preventing expansion thereof in the completed connector or adapter.

An additional object of the invention is to provide a sheet metal terminal connector or adapter embodying the foregoing features of construction and which is readily attached to the electrode of a spark plug in a vehicle in the conventional manner, and which will thereafter be retained in satisfactory electrical connection, notwithstanding the fact that the vehicle might be subjected to excessive vibration during use.

Further objects and advantages, and other new and useful features in the construction, arrangement and general combination of elements of the connector or adapter of the invention will be readily apparent as the following description proceeds with reference to the accompanying drawings, for purposes of illustration but not of limitation, in which like reference characters designate like parts throughout, and in which:

Fig. 1 is a perspective view showing a portion of a spark plug having its threaded electrode fitted with a sheet metal connector or adapter in accordance with the invention, and with the socket type terminal of an associated conductor in position to be attached thereto;

Fig. 2 is a vertical elevational view, on an enlarged scale, showing the improved terminal connector or adapter in applied position on the threaded electrode of a spark plug, for example;

Fig. 3 is a sectional view on line 33 of Fig. 2, looking in the direction of the arrows; and

Fig. 4 shows, on an enlarged scale, the general outline of the sheet metal blank for providing a terminal connector or adapter in accordance with the invention.

Referring now, more particularly, to the drawings, there is illustrated in Figs. 1 and 2 the upper portion of a spark plug P having a connecting stud or electrode 1 in the form of a threaded stem or binding post. The high tension wire or conductor C which is to be detachably connected to the electrode 1 of the spark plug P is provided with a terminal comprising a tubular sheet metal portion 5 defining a substantially rigid socket.

To connect the terminal 5 of the high tension conductor C to the spark plug P, the present invention contemplates the use of a sheet metal connecting device 10 which serves as an adapter that can be quickly attached to the projecting stud or electrode 1 of the spark plug P in a substantially locked connection that is adapted to withstand any degree of vibration to which the engine may be subjected during use. The socket type terminal 5 on the conductor C is adapted for snap fastening engagement with the connector or adapter 10, thus provided, in a manner whereby the conductor C may be readily connected to or disconnected from the spark plug, as desired, and in a minimum of time and effort. While in the present embodiment, the conductor terminal 5 is provided in the form of a tubular socket, the adapter or connector ltl of the present invention is usable with equal effectiveness in connection with the well known spadetype of terminal having the same general application and use.

It is usually preferable that the conductor terminal 5 be attachable to the adapter or connector 10 in any posi' tion of application and otherwise capable of slight swiveling movement as connected to the spark plug P. To this end, the wall of the socket-type terminal 5 is provided with a depression 6 on its periphery which forms an annular detent within said terminal 5 adapted to snap onto the connector or adapter 10 in any position of appliclation and in positive but removable engagement therewit The connector or adapter 10 is a highly simplified, relatively inexpensive form of sheet metal device which lends itself to economical quantity production in that it may be produced at relatively low cost from ordinary sheet metal strip stock with little loss or waste of material. Any suitable sheet metal strip may be employed, preferably that of a spring metal nature such as spring steel which may be heat treated and tempered to provide the connectors or adapters 10 with the desired toughness and hardness.

The connector or adapter 10 is provided in the general construction illustrated in Figs. 1 and 2 from a suitable sheet metal strip or blank, as shown on an enlarged scale in Fig. 4, which is adapted to be rolled into a split tubular body similar to a tubular shell or sleeve, or the like. Preferably interconnecting means are provided on the ends of the blank for locking said ends together to prevent expansion of the split tubular body from its completed form. In a preferred construction, a dovetail locking connection of this character is provided by means of a wedge-shaped projection 12 on one end of the blank which fits into a corresponding wedge-shaped cutout 14 on the other end of the blank. The arrangement is such that the wedge-shaped projection 12 fits in the cutout 14 and lies flush with the adjoining sheet metal surfaces such that both the inner and outer surfaces: of the connector in the region of the connecting elements 12 and 14 are smooth and continuous and lie uniformly in the curved contour of the generally tubular body of the connector 10.

As best seen in Figs. 3 and 4, the outer surface of the blank is provided with spaced generally rectangular depressions defining generally rectangular bosses or protuberances 16 on the inner surface of the blank and in spaced, aligned relation across the inner surface of the blank. When the blank is completed to provide the connector in the form of the generally tubular body 10, these bosses or protuberances 16 project in inwardly offset relation from the inner surfaces of the intermediate or surrounding portions 17 of said tubular body, as seen in Fig. 3, in substantially equally spaced relation around the interior of said tubular body 10.

The inwardly offset generally rectangular bosses or protuberances 16 are provided on their inner faces with a group of spaced parallel flutes or grooves defining thread elements 18 which are inclined slightly upwardly from left to right, as seen in Fig. 4, in accordance with the inclination of the helix of the thread on the threaded stem or electrode 1. Accordingly, in the completed form of the connector 10, said groups of thread elements 18 define a series of thread surfaces on the equally spaced inwardly offset portions 16 on the inner wall of the tubular body of the connector for uniformly engaging a corresponding group of thread convolutions of the thread on the threaded stem or electrode 1 at equally spaced areas around the periphery of said threaded stem 1. The arrangement, otherwise, is such that the said inwardly offset bosses or protuberances 16 support the generally tubular body of the connector 10 in a uniformly balanced construction in radial relation to the threaded stem or electrode 1 substantially in the manner of a solid plug and, therefore, not subject to deformation or distortion. In the present example, the connector or adapter 10 is provided with three equally spaced inwardly offset bosses or protuberances 16 carrying the thread elements 18 but the invention fully contemplates various similar constructions having any other suitable number of such bosses or protuberances provided with similar or equivalent thread elements.

The upper portion of the blank, Fig. 4, is stamped with two integral sections 20 which initially are substantially circular and are suitably bent into a cup-shaped form as seen in Figs. 2 and 4 to provide segments of a spherical dome having shoulder portions 22 defining a substantially annular shoulder on a ball-shaped head which is adapted to connect readily to either a spadetype conductor terminal or a sleeve type conductor terminal 5 as shown in Fig. l, for example. In order to facilitate the bending and forming of said substantially circular sections 20 into such cup-shaped form, suitable horizontal slits 24 are provided at the opposite sides of the junctions thereof with the body of the blank. As best seen in Fig. 2, in the completed connector 10, the ball-shaped sections 20 preferably are provided with a slight spacing similar to a vertical slit 26 merging with the horizontal slits 24 such that said ball-shaped sections 2t"! have a slight limited resiliency providing for the ready attachment or detachment of the conductor terminal 5 in an easy snap fastening action. Thus, the socket type conductor terminal 5 is adapted to slip over the ball-shaped head of the connector defined by the head sections and to compress said head sections 20 slightly as necessary to permit said terminal 5 to advance to fully attached position where the annular detent 6 in said terminal 5 snaps into positive engagement with the annular shoulder 22 on said ball-shaped head 20 of the connector.

The generally tubular body of the connector 10 is substantially rigid as provided in the preferred construction wherein the blank is rolled into a tubular shell and the ends of the blank locked together by the dovetail connection comprising the wedge-shaped projection 12 received in the wedge-shaped cutout 14, as aforesaid. As shown in Fig. 3, the inwardly projecting bosses or protuberances 16 carrying the thread elements 18 are formed by depressions in inwardly offset relation around the inner surface of said tubular body in position for uniform threaded engagement of said thread elements 18 with the stem or electrode 1 while the intermediate or surrounding wall portions 17 of said tubular body are in spaced relation to said threaded stem or electrode 1. The said bosses or protuberances 16, accordingly, are capable of yielding slightly outwardly in a manner whereby the thread engaging elements 18 on said bosses 16 are preferably provided so as to have a resilient thread locking actiionlwith the thread on the threaded stem or electro e The arrangement is such that the thread elements 18 are readily designed for a friction or press fit with the thread on the threaded electrode 1 in a manner whereby the connector may be readily turned by ordinary finger force into threaded engagement with the threaded stem or electrode 1. Under such ordinary finger force, the bosses or protuberances 16 are adapted to expand slightly so that the thread elements 18 have a more or less free running fit with the threaded electrode 1 to permit the connector to be easily and quickly applied to fully attached position on said electrode as shown in Figs. 1 and 2. The said bosses or protuberances 16 thereupon contract slightly to their initial untensioned condition such that the thread elements 18 thereon have a friction or binding fit with the thread surfaces of the thread on the stem or electrode 1 in the manner of a thread locking action which prevents accidental loosening of the connector from its operative fully attached position on said electrode 1.

In the attached position of the connector 10 on the threaded stud or electrode 1, the body and head sections of the connector are necessarily relatively rigid and present a substantially solid plug onto which the conductor terminal 5 is adapted to be easily and quickly connected by a snap fastening action and to be positively retained in connected relation with the electrode or stem 1 of the spark plug P or other electrical device. The rigid solid nature of the connector 10, otherwise, is particularly advantageous in that the conductor terminal 5 may be connected thereto or disconnected therefrom as often as may be necessary or desirable with practically no danger of distortion or mutilation of the connector or adapter 10 from its proper shape and form.

The connector or adapter 10 preferably is constructed of relatively thin sheet metal the thickness of which is selected according to service requirements and the predetermined size of the terminals to be connected thereby- The clip is most effective when provided of spring metal suitably tempered and otherwise treated to give the desired toughness and hardness. A relatively cheap construction of the connector in accordance with the invention may be provided from cold rolled metal such as cold steel which is untempered but of a spring metal nature and capable of providing an effective and reliable connector or adapter, as and for the purposes described.

While the invention has been described in detail with a specific example, such example is intended as an illustration only inasmuch as the invention fully contemplates various modifications which may be provided without departing from the spirit and scope of the invention.

What is claimed is:

l. A terminal connector comprising a piece of sheet metal bent to provide a split tubular body and a pair of opposite substantially hemispherical sections integrally connected to the upper portion of said split tubular body and cooperating to define a resilient ball-shaped head adapted for connection with a conductor terminal, said split tubular body having a plurality of lengthwise depressions spaced around the periphery thereof providing a plurality of inwardly offset longitudinal protuberances projecting from the inner surface of said split tubular body in spaced relation to each other, said longitudinal protuberances being provided with substantially transverse fiutes defining groups of thread elements adapted for uniform threaded engagement with the thread on a threaded electrode.

2. A terminal connector comprising a piece of sheet metal bent to provide a split tubular body and a pair of opposite substantially hemispherical sections integrally connected to the upper portion of said split tubular body and cooperating to define a resilient ball-shaped head adapted for connection with a conductor terminal, one end of said piece of sheet metal having a recess and the other end thereof having a projection received in said recess to lock said ends together, said split tubular body having a plurality of lengthwise depressions spaced around the periphery thereof providing a plurality of inwardly offset longitudinal protuberances projecting from the inner surface of said split tubular body in spaced relation to each other, said longitudinal protuberances being provided with substantially transverse flutes defining groups of thread elements adapted for uniform threaded engagement with the thread on a threaded electrode.

3. A terminal connector comprising a piece of sheet metal bent to provide a split tubular body and a pair of opposite substantially hemispherical sections integrally connected to the upper portion of said split tubular body and cooperating to define a resilient ball-shaped head adapted for connection with a conductor terminal, one end of said piece of sheet metal having a wedgeshaped cutout and the other end thereof having a corresponding wedge-shaped projection received in said cutout to lock said ends together, said split tubular body having a plurality of lengthwise generally rectangular depressions spaced around the periphery thereof providing a plurality of generally rectangular longitudinal protuberances projecting from the inner surface of said split tubular body in spaced relation to each other, said protuberances projecting in resilient relation to the inner References Cited in the file of this patent UNITED STATES PATENTS 807,051 Strong Dec. 12, 1905 1,514,928 Rabezzana Nov. 11, 1924 l,953,593 Douglas Apr. 3, 1934 2,430,543 Tinnerman Nov. 11, 1947 

